1. Field of the Invention
This invention generally relates to marking and inscribing gemstones, particularly diamonds, with indicia identifying the gemstones by directing a laser beam across surface portions of the gemstones.
2. Description of the Related Art
Laser etching or inscribing of a diamond surface for the purpose of permanently identifying a diamond is known. U.S. Pat. No. 4,392,476 to Gresser, et al. employs a Nd:YAG(1.06 xcexcm) laser for graphitizing a series of overlapping successive positions across a diamond girdle to create an identifying indicium. U.S. Pat. No. 4,467,172 to Ehrenwald, et al. describes an inscribing apparatus using a harmonic of the fundamental frequency of a Q-switched YAG laser to mark a diamond girdle. U.S. Pat. No. 5,753,887 to Rosenwasser, et al. discloses the engraving of indicia on gemstones, especially to create decorative markings visible to the human eye on surfaces other than the girdles, by employing a Nd:YAG or a CO2 laser. U.S. Pat. No. 5,932,119 to Kaplan, et al. discloses a solid-state Nd:YLF laser for inscribing diamonds under computer control.
U.S. Pat. Nos. 5,149,938, 5,410,125 and 5,573,684, all to Winston, et al., discloses the use of pulsed gas-discharge excimer lasers (operative at wavelengths from 193 nm to about 351 nm depending on the particular rare gas halide used) for directing the excimer laser beam through an external mask located between the laser and the diamond. The mask has a cutout which defines the mark. The laser beam passing through the cutout irradiates the diamond and forms an image of the cutout on the diamond.
One feature of this invention is a fine control over the output power and resolution of a laser beam by the selection of an aperture within the resonant cavity of the laser.
Another feature of this invention is a preview of the indicia to be inscribed and its location on a diamond by the advance positioning of guidelines across the diamond.
Still another feature of this invention is a topographical mapping of the diamond girdle prior to inscribing.
Yet another feature of this invention is a switching between different modes of inscribing among successive diamonds.
An additional feature of this invention is a manifest on which quality control information is printed.
Another feature of this invention is to increase the throughput of a laser inscribing system by using multiple auxiliary workstations.
Yet another feature of this invention is to control the opening and closing of doors especially those controlling access to the laser for increased safety.